public static void generateJarFile(String from, String location, String name) throws IOException {
    String myJarPath = location + name + ".jar";
    File file = new File(myJarPath);
    JarOutputStream jarOutputStream = new JarOutputStream(new FileOutputStream(file));

    File[] toInputFiles = new File(from).listFiles();

    assert toInputFiles != null;
    for (File singleFile : toInputFiles) {
        JarEntry jarEntry = new JarEntry(singleFile.getPath());
        jarOutputStream.putNextEntry(jarEntry);
        InputStream inputStream = new FileInputStream(singleFile);

        jarOutputStream.write(inputStream.read());
        inputStream.close();
    }
    jarOutputStream.close();
}